Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net loss	$ (17,492)	$ (76,643)
Adjustments to reconcile net loss to cash flows from operating activities:
Gain from sale of Priority Review Voucher	(108,069)
Depreciation and amortization	6,529	4,879
Reduction in the carrying amounts of the right of use assets	2,153	1,491
Amortization of investment discount	(1,284)	(3,476)
Non-cash interest expense	6,342	5,208
Stock-based compensation	24,024	16,139
Other	(1,381)	88
Changes in operating assets and liabilities, net:
Net increase in accounts receivable	(15,996)	(1,466)
Net increase in inventory	(1,789)	(15,022)
Net increase in other assets	(27,966)	(79,564)
Net increase in deferred revenue	820,437	682
Net (decrease) increase in accounts payable, accrued expenses and other liabilities	(57,718)	1,451
Net cash provided by (used in) operating activities	627,790	(146,233)
Cash flows from investing activities:
Purchase of property and equipment	(9,120)	(16,263)
Proceeds from sale of Priority Review Voucher, net of commission	108,069
Purchase of available-for-sale securities	(365,437)	(494,481)
Maturity and sale of available-for-sale securities	250,000	646,830
Other	(1,192)	(855)
Net cash (used in) provided by investing activities	(17,680)	135,231
Cash flows from financing activities:
Proceeds from issuance of common stock to Roche		365,264
Proceeds from exercise of stock options and purchase of stock under the Employee Stock Purchase Program	7,482	12,299
Taxes paid related to net share settlement of equity awards	(4,798)
Net cash provided by financing activities	319,022	377,563
Increase in cash, cash equivalents and restricted cash	929,132	366,561
Cash, cash equivalents and restricted cash:
Beginning of period	843,645	370,829
End of period	1,772,777	737,390
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents	1,764,212	732,190
Restricted cash in other assets	$ 8,565	$ 5,200
Restricted Cash, Noncurrent, Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherAssetsNoncurrent	us-gaap:OtherAssetsNoncurrent
Total cash, cash equivalents and restricted cash	$ 1,772,777	$ 737,390
Supplemental disclosure of cash flow information:
Cash paid during the period for interest	5,385
Supplemental schedule of non-cash investing activities and financing activities:
Issuance costs related to the Roche Collaboration in accrued expenses	4,285
Manufacturing right of use asset additions	27,554
Manufacturing lease liability additions	24,783
Sale of available-for-sale securities included in investment receivable		42,300
Intangible assets and property and equipment included in accrued expenses	6,154	$ 3,108
Roche
Cash flows from financing activities:
Proceeds from issuance of common stock to Roche	$ 316,338